Five: Sexy Straddle.

On Christmas morning, while everyone else was opening presents—or, in Byron, Meredith, and Mike's case, frolicking with deer—Hallbjorn cooked Aria organic pancakes and tofu sausage for a Christmas breakfast. Then he decorated the cactus in the family room with various red items from the house—a mitten, a plastic spoon, a long ribbon he'd found in a drawer. "How did you know I wanted a Christmas tree?" Aria gasped.

Hallbjorn just grinned. "I just had a hunch."

After that Aria had texted Merry Christmas to Emily and Spencer—Hanna was Jewish—and she and Hallbjorn made their way to South Street in Philadelphia. Once there, they skirted around giant snowdrifts that were already yellow with dog pee. The air was biting and crisp, and there was hardly anyone out except for a couple of hard-core joggers and a bunch of tourists with expensive cameras around their necks. The only establishments that were open were a few sex shops and a Walgreens pharmacy, which was already advertising 50 percent off Rudolph and Santa decorations.

"Look, this place sells hemp outerwear!" Aria pointed at a shuttered boutique with a giant marijuana leaf decal in the window. "That's eco, right?"

"As long as it's not made in a sweatshop." Hallbjorn twisted his mouth. "You have to be very careful about organic and hemp fabrics."

Aria nodded sagely, as if she'd known this all along. They'd spent the whole morning playing the green version of "I Spy," pointing out the vegetarian restaurants on South Street, the city's many recycling bins, and the fact that some of the buses ran on natural gas. Hallbjorn had told her that he'd recently dedicated himself to saving the environment. He looked so sexy and earnest while talking about carbon emissions, and Aria found herself wanting to prove just how green she was, too.

"So what made you become so environmentally conscious, anyway?" Aria asked as they passed a vintage store she loved. "I don't remember your being so committed when I was in Iceland."

"I started becoming aware while I was in Norway, but I really got into it when I started this year," Hallbjorn admitted. "I joined an activist group that was trying to stop a big corporation from dumping their waste into the river near the school. A girl named Anja ran it. She set up something amazing protests."

There was a wistful look on his face. "Was Aria…a girlfriend?" Aria asked, trying not to sound jealous or prying.

Hallbjorn stepped around a large blue parking meter that had a plastic Christmas wreath hanging from it. "Yes. But a month ago she joined a Greenpeace boat that attacks whalers off the coast of Japan. I wanted to go too, but she told me she needed to be alone."

"I'm sorry about Anja," Aria said as a passing car honked its horn to "Santa Claus Is Coming to Town." "I recently had my heart broken, too."

"Really?" Hallbjorn raised an eyebrow. "What happened?"

Aria told him some of the details about Ezra, leaving out that he'd been her teacher. "It really hurt when he left. I thought I'd never get over him. But he's probably with a new girl by now."

"Yes, that's how I feel about Anja," Hallbjorn said miserably. "She changed my life. Pushed me to do things I wouldn't have dreamed of. And now…poof." He cupped his palm under his chin and blew, miming a dandelion seed scattering in the wind. "Now she's with a guy who when not saving whales, chains himself to trees in the rainforest that are about to be bulldozed."

Aria snickered. "He's probably not that great. I bet he wets his sleeping bag every night."

"Or perhaps he secretly eats endangered rainforest monkeys," Hallbjorn said, playing along.

"Or he doesn't recycle!"

"What can your ex-boyfriend's new girlfriend's flaw be?" Hallbjorn tapped his chin. "That's she's actually a man?"

Aria burst out laughing. "Maybe she doesn't know how to read. Or maybe she's incredibly hairy, even her butt!"

"Seriously, though," Hallbjorn said, staring deep into her eyes. "We never had any of those problems. Everything with us was just so…easy."

"I know," Aria said, suddenly feeling shy. "We were such a good fit."

Suddenly Hallbjorn froze on the sidewalk. His already pale skin turned even whiter, and he darted around a corner and dove into a small alleyway.

"Hallbjorn?" Aria followed him into the alcove. It smelled like rotting garbage and cigarette butts. A bunch of bicycle tires were propped up against the building. "What's the matter?"

"Shh." Hallbjorn pressed a hand over Aria's mouth. His eyes shifted back and forth from the street corner to the traffic lights. A police car slowly rolled across the intersection. A woman walking a Great Dane passed by on the other side of the street.

Finally, Hallbjorn tiptoed out of the alley and looked around. The color had come back to his face, and he was breathing easier now.

"What was that all about?" Aria asked as she followed him.

"I thought I saw someone I knew."

"Someone…Icelandic? Or one of your family members from New York?"

"It doesn't matter." Hallbjorn took a few more steps down South Street, but then froze again. Aria gazed around to find what could possibly be spooking him. The two old people out for a stroll? The squirrel lurking by the pathetic little tree at the curb?

He ducked into an open door. Aria followed. It was dark and chilly inside the building, and the scent of essential oils made Aria dizzy. A waterfall burbled, and wind chimes clanged together in the window, Double Moon Yoga Studio, said a sign on the far wall. There were posters of lithe people in various poses all over the walls. Several pairs of shoes rested in square cubbies off to the left, and a few people calmly waited for a class to begin in a large, airy room to the right.

A girl wearing a Santa hat beamed at them from behind the front desk. "Namaste," she said in a Zen-like voice. "Happy holidays. Are you here for the couples class?"

"Uh, yes," Hallbjorn said. He glanced at Aria. "Is that okay?"

Aria stared at him crazily. They hadn't discussed doing yoga. She pivoted and peered out of the window again. What did he think he saw outside?

Then she realized Santa Hat had said couples class. Meaning sexy stretching…with Hallbjorn. "It's totally okay," she answered, plunging her hand into her wallet and plucking twenty dollars on the counter.

After changing into some clean sweats from the studio's clothes exchange bin, Aria and Hallbjorn emerged from their respective dressing rooms. Hallbjorn looked much calmer, but Aria touched his arm anyway. "Are you okay? You were acting strange back there."

"I'm fine," Hallbjorn answered. "I was just a little stressed. Yoga always makes me feel better."

They grabbed mats and walked into the practice room. The Santa hat—wearing girl who'd manned the front desk stood against the mirror in the front. A tall guy with a Jesus beard, droopy eyes, and wearing spandex leggings without a shirt joined her and turned to face Aria, Hallbjorn, and the two other couples in the room. "I'm glad you could all be with us today. This is a very special couples class, being that it's on Christmas Day," he said. "Lie down on the floor. Breathe in and out in the same rhythm. Feel as one."

Hallbjorn dropped to his mat. Aria lay in corpse pose too, trying to ignore the fact that the mat kind of smelled like feet. She peeked at Hallbjorn next to her. His chest was rising up and down in an even cadence.

"This practice is all about being bound together in acceptance, unity, and love," Santa hat explained after they'd breathed for a few more minutes. "It will lead to being more open and productive as a couple. First, we're going to do something called the double tree."

She told the three couples in the room to stand hip-to-hip and wrap their arms around each other's waists. Aria did so, shooting Hallbjorn a nervous smile. His arm felt strong and secure around her back.

"Now raise your opposite legs into tree pose," Jesus Beard said, demonstrating with Santa Hat. "Touch the palm of your free hand to your partner's. See? It binds you together."

Aria felt Hallbjorn's balance shift as he bent his knee and placed his foot on the inside of his thigh. She did the same, pressing her hand into Hallbjorn's. Instead of leaving his hand limp against her palm, as the instructors and the other couples in the room were doing, he laced his fingers with hers and squeezed.

"Thaaaat's right." Jesus Beard's eyes were closed. "Feel the energy. Feel your equality. You are two trees in nature, holding one another up."

"This is a lot like your Solstice rituals, no?" Hallbjorn asked.

Aria giggled. "Next they're going to ask us to run naked up South Street."

Hallbjorn raised his eyebrows. "I'd do it if you would."

It took everything in Aria's power not to blush.

"Now we're going to move into the double straddle." Santa Hat lowered her bent knee to the ground. "This really helps you and your partner get over all sensitivities and insecurities with one another. Sit on your mats. Open your legs in a V, face each other, and hold hands. Just like this."

The instructors moved into the pose. Both of them were extremely limber; their legs jackknifed into two nearly perfect splits. They inched forward toward one another until their groins were practically touching.

Aria giggled nervously. Hallbjorn was already stretching his legs into a straddle. Aria did the same, then grabbed Hallbjorn's hands. Slowly, they pulled each other closer together, leaning forward so that their faces almost touched. Aria caught Hallbjorn's eye and didn't look away. Hallbjorn didn't either.

She flattened her spine, inched forward, and touched her lips to his. His mouth was warm and firm and tasted like honey. And for the first time in months, she didn't think about Ezra or Ali or A at all.